Coco Gauff revels in 128 mph serve, balances Serena watch schedule with US Open campaign

WATCH: Gauff's big serves have helped her to impressive wins throughout the summer, including one over Aryna Sabalenka in Canada.

NEW YORK—Coco Gauff enjoyed a quick day of US Open action on Wednesday, and emphasized her need for speed by striking a 128 mph serve in her 6-2, 7-6 (4) victory over Elena-Gabriela Ruse.

The serve is officially the fifth-fastest ever struck by a woman, and the third-fastest in US Open history behind Venus Williams (2007) and Alycia Parks (2021)—both of whom clocked in at 129 mph.

“I don't know how that happened,” the surprised 18-year-old said after the match. “It didn't feel like I hit it that hard. Sometimes I feel like when you try to hit the serve hard, it still goes fast, but that was not supposed to be that hard.

“I kind of looked at her after. I hit, like, a couple good serves that game, likes in the 120s. She was laughing at her box. I was like, ‘I don't know what's going on either.’”

Gauff came close to that speed at Wimbledon when she struck a 124 mph serve against Mihaela Buzarnescu, and while it may not have been intentional, it was a strong serving day that helped her surge into the third round in time to watch at least some of Serena Williams in her match against No. 2 seed Anett Kontaveit under the Arthur Ashe Stadium lights.

I hit, like, a couple good serves that game, likes in the 120s. She was laughing at her box. I was like, ‘I don't know what's going on either.' Coco Gauff

“I'll be watching TV here on-site,” explained the No. 12 seed. “Maybe at the end if it's not too late I'll catch the end of it.

“Like I said, I have doubles tomorrow. If it goes three sets, I probably won't be staying till the end unfortunately. I would love to, but that's the problem when you have to play and when you like tennis as a fan, too. You got to balance the two.”

That balance has translated to her game, which she’ll need to maintain in order to overcome 2017 finalist Madison Keys in her next match.

“I think my serve is a lot better. I'm winning a lot of first-serve points. Forehand has improved a lot. Return has improved. Also just my mentality on the court. Today down Love-30, 5-3, definitely could have threw it in the can and got ready for the third set. Same at 15-40. But I didn't.

“I feel like that shows growth. I feel like in the past, those are games I would have lost. Yeah, it's about learning, and I think I'm learning.”